A non-linear dynamic analysis of heavy haul track line sleepers under wheel flat

Significant wheel-rail dynamic forces occur because of imperfections in the wheels and/or rail. One of the key responses to the transmission of these forces down through the track is impact force on the sleepers. Dynamic analysis of nonlinear systems is very complicated and does not lend itself easily to a classical solution of multiple equations. Trying to deduce the behaviour of track components from experimental data is very difficult because such data is hard to obtain and applies to only the particular conditions of the track being tested. The finite element method can be the best solution to this dilemma. This paper describes a finite element model using the software package ANSYS for various sized flat defects in the tread of a wheel rolling at a typical speed on heavy haul track. The paper explores the dynamic response of a prestressed concrete sleeper to these defects.

Underground power cable environment on-line monitoring and analysis

Knowledge of cable parameters has been well established but a better knowledge of the environment in which the cables are buried lags behind. Research in Queensland University of Technology has been aimed at obtaining and analysing actual daily field values of thermal resistivity and diffusivity of the soil around power cables. On-line monitoring systems have been developed and installed with a data logger system and buried spheres that use an improved technique to measure thermal resistivity and diffusivity over a short period. Results based on long term continuous field data are given. A probabilistic approach is developed to establish the correlation between the measured field thermal resistivity values and rainfall data from weather bureau records. This data from field studies can reduce the risk in cable rating decisions and provide a basis for reliable prediction of “hot spot” of an existing cable circuit

Implementation Guide for Surveillance of Central Line Associated Bloodstream Infection -- [Consultation Edition]

The implementation guide for the surveillance of CLABSI in intensive care units (ICU) was produced by the Healthcare Associated Infection (HAI) Technical Working Group of the Australian Commission on Safety and Quality in Health Care(ACSQHC), and endorsed by the ACSQHC HAI Advisory Committee. State surveillance units, the ACSQHC and the Australian and New Zealand Intensive Care Society (ANZICS) have representatives on the Technical Working Group, and have provided input into this document.

Optimal distribution network reinforcement considering load growth, line loss, and reliability

In this paper, a new comprehensive planning methodology is proposed for implementing distribution network reinforcement. The load growth, voltage profile, distribution line loss, and reliability are considered in this procedure. A time-segmentation technique is employed to reduce the computational load. Options considered range from supporting the load growth using the traditional approach of upgrading the conventional equipment in the distribution network, through to the use of dispatchable distributed generators (DDG). The objective function is composed of the construction cost, loss cost and reliability cost. As constraints, the bus voltages and the feeder currents should be maintained within the standard level. The DDG output power should not be less than a ratio of its rated power because of efficiency. A hybrid optimization method, called modified discrete particle swarm optimization, is employed to solve this nonlinear and discrete optimization problem. A comparison is performed between the optimized solution based on planning of capacitors along with tap-changing transformer and line upgrading and when DDGs are included in the optimization.

The Brisbane Line

A short 27 mins docudrama film. The Brisbane Line is a neo noir drama-documentary depicting the forgotten history surrounding the subtropical capital of Queensland, Australia. Set in the shadows of this sunshine city's unsolved crime, the film explores gaps between fact and fiction, memory and myth and excavates Brisbane's original sin [from DVD container]. The Brisbane Line is a film noir about the 1940s police force & corruption in Brisbane. The film is a creative research output, screened at Tribal Cinemas, Brisbane on the 8th November 2011.

Advanced battery storage control for an autonomous microgrid

A new control method for battery storage to maintain acceptable voltage profile in autonomous microgrids is proposed in this article. The proposed battery control ensures that the bus voltages in the microgrid are maintained during disturbances such as load change, loss of micro-sources, or distributed generations hitting power limit. Unlike the conventional storage control based on local measurements, the proposed method is based on an advanced control technique, where the reference power is determined based on the voltage drop profile at the battery bus. An artificial neural network based controller is used to determine the reference power needed for the battery to hold the microgrid voltage within regulation limits. The pattern of drop in the local bus voltage during power imbalance is used to train the controller off-line. During normal operation, the battery floats with the local bus voltage without any power injection. The battery is charged or discharged during the transients with a high gain feedback loop. Depending on the rate of voltage fall, it is switched to power control mode to inject the reference power determined by the proposed controller. After a defined time period, the battery power injection is reduced to zero using slow reverse-droop characteristics, ensuring a slow rate of increase in power demand from the other distributed generations. The proposed control method is simulated for various operating conditions in a microgrid with both inertial and converter interfaced sources. The proposed battery control provides a quick load pick up and smooth load sharing with the other micro-sources in a disturbance. With various disturbances, maximum voltage drop over 8% with conventional energy storage is reduced within 2.5% with the proposed control method.

Calling for help : a responsive evaluation of Child Health Line

The project examined the responsiveness of the telenursing service provided by the Child Health Line (hereinafter referred to as CHL). It aimed to provide an account of population usage of the service, the call request types and the response of the service to the calls. In so doing, the project extends the current body of knowledge pertaining to the provision of parenting support through telenursing. Approximately 900 calls to the CHL were audio-recorded over the December 2005-2006 Christmas-New Year period. A protocol was developed to code characteristics of the call, the interactional features between the caller and nurse call-taker, and the extent to which there was (a) agreement on problem definition and the plan of action and (b) interactional alignment between nurse and caller. A quantitative analysis examined the frequencies of the main topics covered in calls to the CHL and any statistical associations between types of calls, length of calls and nurse-caller alignment. In addition, a detailed qualitative analysis was conducted on a subset of calls dealing with the nurse management of calls seeking medical advice and information. Key findings include: • Overall, 74% of the calls discussed parenting and child development issues, 48% discussed health/medical issues, and 16% were information-seeking calls. • More specifically: o 21% discussed health/medical and parenting and child development issues. o 3% discussed parenting and information-seeking issues. o 5% discussed health/medical, parenting/development and information issues. o 18% exclusively focussed on health and medical issues and therefore were outside the remit of the intended scope of the CHL. These calls caused interactional dilemmas for the nurse call-takers as they simultaneously dealt with parental expectations for help and the CHL guidelines indicating that offering medical advice was outside the remit of the service. • Most frequent reasons for calling were to discuss sleep, feeding, normative infant physical functions and parenting advice. • The average length of calls to the CHL was 7 minutes. • Longer calls were more likely to involve nurse call-takers giving advice on more than one topic, the caller displaying strong emotions, the caller not specifically providing the reason for the call, and the caller discussing parenting and developmental issues. • Shorter calls were characterised by the nurse suggesting that the child receive immediate medical attention, the nurse emphasising the importance or urgency of the plan of action, the caller referring to or requesting confirmation of a diagnosis, and caller and nurse call-taker discussion of health and medical issues. • The majority of calls, 92%, achieved parent-nurse alignment by the conclusion of the call. However, 8% did not. • The 8% of calls that were not aligned require further quantitative and qualitative investigation of the interactional features. The findings are pertinent in the current context where Child Health Line now resides within 13HEALTH. These findings indicate: 1. A high demand for parenting advice. 2. Nurse call-takers have a high level of competency in dealing with calls about parenting and normal child development, which is the remit of the CHL. 3. Nurse call-takers and callers achieve a high degree of alignment when both parties agree on a course of action. 4. There is scope for developing professional practice in calls that present difficulties in terms of call content, interactional behaviour and call closure. Recommendations of the project: 1. There are numerous opportunities for further research on interactional aspects of calls to the CHL, such as further investigations of the interactional features and the association of the features to alignment and nonalignment. The rich and detailed insights into the patterns of nurse-parent interactions were afforded by the audio-recording and analysis of calls to the CHL. 2. The regular recording of calls would serve as a way of increasing understanding of the type and nature of calls received, and provide a valuable training resource. Recording and analysing calls to CHL provides insight into the operation of the service, including evidence about the effectiveness of triaging calls. 3. Training in both recognising and dealing with problem calls may be beneficial. For example, calls where the caller showed strong emotion, appeared stressed, frustrated or troubled were less likely to be rated as aligned calls. In calls where the callers described being ‘at their wits end’, or responded to each proposed suggestion with ‘I’ve tried that’, the callers were fairly resistant to advice-giving. 4. Training could focus on strategies for managing calls relating to parenting support and advice, and parental well-being. The project found that these calls were more likely to be rated as being nonaligned. 5. With the implementation of 13HEALTH, future research could compare nurse-parent interaction following the implementation of triaging. Of the calls, 21% had both medical and parenting topics discussed and 5.3% discussed medical, parenting and information topics. Added to this, in 12% of calls, there was ambiguity between the caller and nurse call-taker as to whether the problem was medical or behavioural.

Procuring OSM : base-line models of off-site manufacture business processes in Australia

A pressing cost issue facing construction is the procurement of off-site pre-manufactured assemblies. In order to encourage Australian adoption of off-site manufacture (OSM), a new approach to underlying processes is required. The advent of object oriented digital models for construction design assumes intelligent use of data. However, the construction production system relies on traditional methods and data sources and is expected to benefit from the application of well-established business process management techniques. The integration of the old and new data sources allows for the development of business process models which, by capturing typical construction processes involving OSM, provides insights into such processes. This integrative approach is the foundation of research into the use of OSM to increase construction productivity in Australia. The purpose of this study is to develop business process models capturing the procurement, resources and information flow of construction projects. For each stage of the construction value chain, a number of sub-processes are identified. Business Process Modelling Notation (BPMN), a mainstream business process modelling standard, is used to create base-line generic construction process models. These models identify OSM decision-making points that could provide cost reductions in procurement workflow and management systems. This paper reports on phase one of an on-going research aiming to develop a proto-type workflow application that can provide semi-automated support to construction processes involving OSM and assist in decision-making in the adoption of OSM thus contributing to a sustainable built environment.

Exponential asymptotics of free surface flow due to a line source

The steady problem of free surface flow due to a submerged line source is revisited for the case in which the fluid depth is finite and there is a stagnation point on the free surface directly above the source. Both the strength of the source and the fluid speed in the far field are measured by a dimensionless parameter, the Froude number. By applying techniques in exponential asymptotics, it is shown that there is a train of periodic waves on the surface of the fluid with an amplitude which is exponentially small in the limit that the Froude number vanishes. This study clarifies that periodic waves do form for flows due to a source, contrary to a suggestion by Chapman & Vanden-Broeck (2006, J. Fluid Mech., 567, 299--326). The exponentially small nature of the waves means they appear beyond all orders of the original power series expansion; this result explains why attempts at describing these flows using a finite number of terms in an algebraic power series incorrectly predict a flat free surface in the far field.

Morphology-based model for predicting osteocyte-like cell line (MLO-Y4) growth process

This work has led to the development of empirical mathematical models to quantitatively predicate the changes of morphology in osteocyte-like cell lines (MLO-Y4) in culture. MLO-Y4 cells were cultured at low density and the changes in morphology recorded over 11 hours. Cell area and three dimensional shape features including aspect ratio, circularity and solidity were then determined using widely accepted image analysis software (ImageJTM). Based on the data obtained from the imaging analysis, mathematical models were developed using the non-linear regression method. The developed mathematical models accurately predict the morphology of MLO-Y4 cells for different culture times and can, therefore, be used as a reference model for analyzing MLO-Y4 cell morphology changes within various biological/mechanical studies, as necessary.

Designing a new robust on-line secondary path modeling technique for feedforward active noise control systems

Several approaches have been introduced in the literature for active noise control (ANC) systems. Since the filtered-x least-mean-square (FxLMS) algorithm appears to be the best choice as a controller filter, researchers tend to improve performance of ANC systems by enhancing and modifying this algorithm. This paper proposes a new version of the FxLMS algorithm, as a first novelty. In many ANC applications, an on-line secondary path modeling method using white noise as a training signal is required to ensure convergence of the system. As a second novelty, this paper proposes a new approach for on-line secondary path modeling on the basis of a new variable-step-size (VSS) LMS algorithm in feed forward ANC systems. The proposed algorithm is designed so that the noise injection is stopped at the optimum point when the modeling accuracy is sufficient. In this approach, a sudden change in the secondary path during operation makes the algorithm reactivate injection of the white noise to re-adjust the secondary path estimate. Comparative simulation results shown in this paper indicate the effectiveness of the proposed approach in reducing both narrow-band and broad-band noise. In addition, the proposed ANC system is robust against sudden changes of the secondary path model.

Sediment-transport (wind) experiments in zero gravity

The carousel wind tunnel (CWT) can be a significant tool for the determination of the nature and magnitude of interparticlar forces at threshold of motion. By altering particle and drum surface electrical properties and/or by applying electric potential difference across the inner and outer drums, it should be possible to separate electrostatic effects from other forces of cohesion. Besides particle trajectory and bedform analyses, suggestions for research include particle aggregation in zero and sub-gravity environments, effect of suspension-saltation ratio on soil abrasion, and the effects of shear and shear free turbulence on particle aggregation as applied to evolution of solar nebula.

Bubble extinction in Hele-Shaw flow with surface tension and kinetic undercooling regularisation

We perform an analytic and numerical study of an inviscid contracting bubble in a two-dimensional Hele-Shaw cell, where the effects of both surface tension and kinetic undercooling on the moving bubble boundary are not neglected. In contrast to expanding bubbles, in which both boundary effects regularise the ill-posedness arising from the viscous (Saffman-Taylor) instability, we show that in contracting bubbles the two boundary effects are in competition, with surface tension stabilising the boundary, and kinetic undercooling destabilising it. This competition leads to interesting bifurcation behaviour in the asymptotic shape of the bubble in the limit it approaches extinction. In this limit, the boundary may tend to become either circular, or approach a line or "slit" of zero thickness, depending on the initial condition and the value of a nondimensional surface tension parameter. We show that over a critical range of surface tension values, both these asymptotic shapes are stable. In this regime there exists a third, unstable branch of limiting self-similar bubble shapes, with an asymptotic aspect ratio (dependent on the surface tension) between zero and one. We support our asymptotic analysis with a numerical scheme that utilises the applicability of complex variable theory to Hele-Shaw flow.

Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the ‘zero-scan’ method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner’s x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels.